1. Field of Invention
Exemplary embodiments of the present invention relate to a pixel structure for an electro-optical apparatus, such as a liquid crystal device and an organic EL (electro-luminescence) device. Exemplary embodiments include the electro-optical apparatus using the pixel structure and an electronic instrument, such as a liquid crystal projector, a mobile phone, and a hand-held information terminal.
2. Description of Related Art
A delta arrangement can display high-quality images with low-capacitance image data, and it is thereby suitable for displaying images, such as natural paintings. However, problems arise in that line drawings, such as characters and figures, become unclear. Thus, in an electro-optical apparatus mainly displaying character data, such as a computer monitor, an RGB stripe arrangement has been used in accordance with the related art. However, the stripe arrangement requires high-capacitance image data more than in the delta arrangement. That is, when data are transmitted with a limited band, a load is applied thereto so as to also require a large-capacitance image memory. The electro-optical apparatus also requires high resolution.
Related art mobile instruments allow for information obtained from Internet to be displayed on a mobile display. When digitalized terrestrial broadcasting is delivered in accordance with MPEG-4 (motion picture experts groups-4) in the future, television images can be viewed and listened on the mobile display. Since the communication speed over a radio communication network for mobile instruments including a mobile phone network, is slower than those over an ADSL (asymmetric digital subscriber line) and a FITH (fiber to the home), it is preferable that high-quality images can be displayed with as lower capacitance data as possible. However, both images and line drawings cannot be compatibly displayed.
On the other hand, for fixed appliances, such as televisions and personal computers, the environment in that high-quality images can be obtained through a massive high-speed communication network and digital broadcasting is going to be prepared. However, since human sensibility in visual characteristics is higher in the horizontal and vertical directions, there is a problem in that with a square pixel arrangement, the pixel structure is perceivable even using high-resolution data. Thus, apparatuses capable of compatibly displaying both images and line drawings in high quality under any environment are required.
In related art documents, instead of a delta arrangement of square pixels, a technique has been proposed in that lines in horizontal and vertical directions, which are perceivable with square pixels, are reduced by aligning pseudo-hexagonal pixels in a delta arrangement so as to form a so-called honeycomb structure using hexagonal or a number of pixels, as disclosed in related art document Japanese Unexamined Patent Application Publication No. 9-233383 (P. 4 to 5, FIG. 4).
In order to enhance or improve the display quality of character data in the delta arrangement, related art documents disclose a structure that includes color filters arranged corresponding to pixel electrodes aligned in a stripe arrangement, each having an area smaller than that of the pixel electrode, so that centers of the color filters are aligned in a substantial delta arrangement, see for example related art document Japanese Unexamined Patent Application Publication No. 2001-337317 (P. 3, FIG. 1).
In electro-optical apparatuses such as organic EL devices, a technique of aligning sub-pixels in a delta arrangement has been disclosed in related art document Japanese Unexamined Patent Application Publication No. 2002-221917 (P. 3, FIG. 1), for example.